Abstract: Saturated sand soil liquefaction may cause severe damage to tunnels under seismic loading. Accurately evaluating the liquefaction properties of the strata through which tunnels pass and taking anti-liquefaction measures can effectively reduce the seismic damages to tunnels. Based on the Seed method, a numerical simulation technique is used to analyze the changes to the liquefaction properties of surrounding stratum before and after tunnel excavation. The results show that: excavation disturbance can effectively reduce the liquefaction resistance of a stratum, and the reduction degree of the liquefaction resistance at the bottom is a little bit smaller than that of the haunch; with the increase of distance away from the tunnel excavation center, the influence of tunnel excavation on the liquefaction properties of a stratum decreases; the larger the overburden, the less effect excavation has on the liquefaction properties of the stratum; the influence of the excavation disturbance should be taken into account when the liquefaction properties of a stratum through which a tunnel passes is evaluated.